The cloudy liquid around canned chickpeas used to be poured down the drain automatically. It is now known as aquafaba and can replace some of the functional roles of egg white in cooking. Its useful behavior comes from small amounts of chickpea proteins, starches, sugars and other soluble solids that have moved into the water during processing. The concentration varies, so one can may whip beautifully while a very dilute homemade batch needs reduction.
Aquafaba is cooking liquid, not a separate ingredient from the bean
When chickpeas soak and cook, water moves into the seed while some soluble material moves out. Proteins, carbohydrates and other compounds accumulate in the surrounding liquid. Canning combines heat, water and time in a closed system, often producing a liquid with useful consistency straight from the container.
Homemade chickpea water can work too. If it looks almost like plain water and fails to whip, gently reducing it concentrates the dissolved solids. Cool it before assessing viscosity because hot liquid can seem thinner than the same batch after refrigeration.
Why it can make a foam
Whipping introduces countless air bubbles. Surface-active molecules in aquafaba help coat those air-water interfaces, while viscosity slows drainage of liquid from between bubbles. Together those effects allow a foam to form and persist long enough for meringues, mousses or aerated batters.
Aquafaba is not chemically identical to egg white and generally contains much less protein. Its performance depends on concentration, pH, sugar, mixing equipment and brand. Recipes that rely heavily on egg proteins for structure may need different treatment rather than a simple spoon-for-spoon substitution.
It can also emulsify and thicken
The same mixture of proteins and carbohydrates can help keep oil and water dispersed, which is why aquafaba works in mayonnaise-style sauces and dressings. It can also add body to batters and some desserts without contributing the flavor or fat of an egg yolk.
These functions overlap but are not identical. A liquid that makes good foam may not produce the same emulsion stability as another batch. If consistency is critical, test a small amount before committing an entire recipe.
Nutrition is modest and highly variable
A 2024 systematic review reported broad composition ranges, with roughly 2.03–2.59 grams of carbohydrate, 0.08–2.8 grams of protein and about 0.07–0.1 grams of fat per 100 milliliters across studied preparations. The wide protein range shows why aquafaba cannot be assigned one universal nutrition profile.
It is therefore better viewed as a functional cooking liquid than as a protein-rich replacement for whole chickpeas or eggs. If the can contains added salt, the liquid can also carry sodium, which matters in sweet recipes or sodium-restricted diets.
Canned and homemade versions need different judgment
Canned aquafaba is convenient because commercial processing often creates a repeatable concentration, although brands still differ. Homemade water depends on bean-to-water ratio, soaking, cooking method and how much liquid remains. Pressure-cooked chickpeas can produce excellent aquafaba when the final liquid is sufficiently concentrated.
A useful visual clue is a slightly viscous consistency similar to loose egg white after cooling. If a recipe fails because the aquafaba is watery, reducing it may work better than simply whipping longer. If it is extremely thick, a small dilution can sometimes help.
Use recipe performance rather than a rigid conversion
Many recipes use rough tablespoon equivalents for one egg or egg white, but aquafaba is not standardized enough for every conversion to behave identically. Meringue, cake, mayonnaise and mousse demand different properties, and sugar or acid can change stability.
Treat aquafaba as a variable functional ingredient. Canned chickpea liquid is the easiest starting point, homemade versions can be concentrated, and the best measure is whether the foam or emulsion behaves as the recipe requires rather than whether a fixed number of tablespoons was used.
Aquafaba also reduces food waste by turning a liquid that would otherwise be discarded into a useful ingredient. That practical benefit is separate from nutrition: the whole chickpeas remain the main source of fiber and protein. Use the beans in the meal and the liquid where its foaming or emulsifying properties solve a recipe problem.
Sources
- PubMed — Chickpea aquafaba systematic review — 2024 review of aquafaba composition, preparation and functional properties.
- PubMed — Composition and Properties of Aquafaba — Characterizes commercial chickpea aquafaba and its foaming, emulsifying and thickening behavior.